Gas lasers, in particular CO2 lasers, generally have a folded laser resonator in which the laser beam is folded in one or more parallel planes which are located one above the other, for which there are arranged in each plane mirror elements which are conventionally accommodated in a plurality of corner housings. Discharge pipes having electrodes for exciting the laser gas are arranged between the corner housings. The laser gas is supplied by a fan as a pressure source which may be constructed, for example, as a radial fan, to the corner housings by means of supply lines. A heat exchanger of a first cooling circuit is generally arranged in this instance in a respective supply line or a supply housing in order to cool the laser gas before entry into the corner housing and consequently into the beam guiding space. The laser gas circuit of the gas laser is closed by means of suction lines or suction housings, via which the heated laser gas is drawn from the discharge pipes and supplied to the (radial) fan. In such a suction line, a heat exchanger of a second cooling circuit which is typically independent of the first (that is to say, which is provided with a separate cooling medium flow) may also be provided in order to cool the laser gas before supply to the radial fan.
DE 10 2008 013 816 B4 discloses a method and a device for recovering energy from a laser processing system in which a gas laser can be used, for example, as a laser source. When the laser processing system is operated, thermal energy is produced with a maximum temperature TMAX. This thermal energy is removed from the laser processing system up to a limit temperature TZ<TMAX and made available to an energy recovery device. The limit temperature TZ in this instance forms the temperature threshold from which the energy recovery device can be used.
In one embodiment of DE 10 2008 013 816 B4, the laser processing system has a gas laser which is constructed as described above and in which heat exchangers are provided in the suction housings or in the supply housings. In order to be able to operate the energy recovery system with the highest possible limit temperature TZ, the highest possible cooling medium discharge temperature is sought, which is intended to be obtained by means of the greatest possible difference between a laser gas temperature before flowing through a heat exchanger and the laser gas temperature after flowing through the heat exchanger. The heat exchanger or the cooling ribs of the heat exchanger are preferably intended to be provided either in the discharge housing or in the supply housing in order to prevent gradual cooling of the laser gas.
An object of the present invention is to develop a cooling arrangement for a gas laser, a gas laser and a method of the type discussed above, having beneficial thermal efficiency.